This invention relates to a bias tire for an aircraft having a laminate formed by laminating a plurality of plies reinforced by organic fiber cords having a large thermal contraction coefficient to intersect with each other and bead cores around which both ends of part of the plies are turned up.
Bias tires for aircraft sometimes undergo running on the ground over long distances, running on the ground or running for taking-off and landing under double loaded conditions (in case of twin wheels, one of which has failed and the other is subjected to twice load) in an emergency. In such running, cords in plies constituting the tire particularly in the proximity of beads are frequently mechanically fatigued and deteriorated due to heat. An accumulation of such bad conditions results in breaking down of the cords and finally damage to the tire.
In order to prevent such a failure, it has been proposed to increase the number of plies of sidewalls of a tire, particularly at bead portions to improve rigidity of the tire to decrease deformation upon being loaded, thereby reducing mechanical strains produced in the cords near to the bead portions. It has also proposed to increases the rubber thickness between adjacent plies so that deformation of the tire is absorbed by shearing deformations of the thick rubber, thereby reducing mechanical strains produced in the cords near the bead portions.
However, these tires as proposed have a disadvantage of considerably increased weight although durability of the bead portions is improved to a certain extent.